1. Field of the Invention
The present invention relates generally to object retaining or anchoring members, and more particularly to such members as are molded within a flow able or formable material that subsequently hardens there around.
2. Background
Many structures are formed by the subsequent hardening of a material such as cement or various types of plastics or epoxies. Such structures are often formed by a mold and also can include anchor structures that may extend from the molded structure and/or serve as a means to retain a further object to the molded structure. An example would include a plastic molded structure requiring support legs where the legs are threadably engaged with the structure after its formation. A particular example would be seen in a roto-molded ice bin structure used to retain therein a volume of ice. During the roto-molding formation thereof it is known to include leg-retaining anchors at the four corners of the base end thereof. These anchors include a retaining means such as a threaded nut to which the legs can be threadably engaged subsequent to the molding process. However, a problem with prior art leg anchors of this type can be the load strength limit thereof. Leg anchors as are known today can become loose from torsional and linear weight forces applied thereto whereby the surrounding plastic can be stretched and deformed. As a result, the anchor can become loose and even detach from the surrounding plastic rendering the leg useless. Accordingly, it would be desirable to have an object retaining anchor that is more securely attached to the plastic molded structure and more resistant to any forces tending to pull it loose therefrom.
The present invention comprises an anchor that in an exemplary embodiment comprises a sheet metal plate having an upturned flange surface extending around a perimeter thereof. The perimeter flange includes a plurality of holes there through and the plate has a threaded nut secured centrally thereof. In one application, the anchor herein is placed within a roto-molded mold for the structure being produced, such as, an ice-retaining bin. Thus, one anchor is placed in each of the four corners of what will be the base of the bin. Each anchor is secured to the bottom of the mold by a bolt anchored through corresponding holes in the mold base and screwed to and engaged with the central threaded nut. The flanges are oriented to extend into the mold, that is, in the opposite direction from what will be the bottom end of the base from which the legs will extend. The bin is then formed by the roto-molding process whereby the plastic material flows over and around the exposed surfaces of the anchor. Specifically, the plastic flows through the holes in the perimeter flanges providing for a strong mechanical locking or securing of the anchor to and with the plastic. Those of skill will understand that the flowing of the plastic through and around the flange holes provides for a mechanically stronger engagement between the plastic and the anchor as compared to a situation where there only exists surface area to surface area contact there between. After the roto-molding process is completed, the retaining bolts are removed and the bin is removed from the mold. It is then possible to attach the legs by threadable engagement with the central threaded nuts of the anchors. The anchors of the present invention were found to provide for surprising improvements in the strength and durability thereof. Destructive testing failed to cause separation of the anchor from the immediately surrounding and covering plastic.